As you know, tomorrow marks 10 years since the terrorist attacks that changed our country forever. Of the nearly 3,000 people killed on 9/11, more than 2,700 died in New York City at the World Trade Center site.

I have a story to tell you about the men and women whose dedication and courage came to inspire all of us in the days and years since. The firefighters, the police officers at Ground Zero were looking for survivors. They were clearing debris, doing whatever they could to help.

Now, they didn't know it at that time, but they were also putting their own lives at risk. And today, many of them are sick and asking whether more could have been done to prevent it.

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UNIDENTIFIED MALE: The trade centers here in New York have been hit by airplanes. In Washington, there is a large fire at the Pentagon.

(SIREN WAILING)

UNIDENTIFIED MALE: The whole building came down.

UNIDENTIFIED MALE: Move it. Get out of here!

UNIDENTIFIED MALE: Back! Back!

UNIDENTIFIED MALE: Get out of here!

UNIDENTIFIED MALE: The president was in Florida today.

GUPTA (voice-over): Within moments after the first tower disintegrated, an eerie silence fell over Lower Manhattan.

DR. DAVID PREZANT, FDNY: There should be a sound when one of the largest skyscrapers in the world collapses. We know that there must have been a sound. Very few people, including myself, remember a sound.

GUPTA: Dr. David Prezant, a pulmonologist and the top doctor with the New York City Fire Department rushed to Ground Zero to help. He was there when the first tower fell.

PREZANT: We are talking about mid-morning, 10:00 or so. It was a very sunny day that morning. It was like it was a little bit darker than dust. You couldn't see your hand in front of your face.

You were suffocating on large particles that were stuck in the back of your throat and nose. And then, there was this fine dust that you were constantly choking on.

GUPTA: In the city, they called the firefighters New York's bravest. And for more than 20 years, Marty Fullam was one of them.

On September 11th, while most people were running from Ground Zero, he was an indisputable hero running toward the fires, the tragedy and all that dust.

(on camera): What is it like for you?

MARTY FULLAM: To walk?

GUPTA: Yes.

FULLAM: I could feel I'm getting a little winded, but I'm OK.

GUPTA: If you didn't have oxygen --

FULLAM: I'd be back in bed now.

GUPTA (on voice): Four years after working at Ground Zero, Fullam became gravely ill.

(on camera): You got sick.

FULLAM: Yes, sir.

GUPTA: And now, at least some doctors have said this could have been due to inhaling those particles down at Ground Zero?

FULLAM: Yes. At first I was surprised. It was 9/11? It's four years later. But the doctors pretty much said, it's what it is. Yes, they said, yes, this is 9/11.

GUPTA: He had the World Trade Center cough initially.

PREZANT: Initially.

GUPTA: That is a term you coined.

PREZANT: Yes.

GUPTA: People think cough and they think how bad could a cough be?

PREZANT: Right.

GUPTA: How bad was it? PREZANT: In retrospect, we shouldn't have called it World Trade Center cough. We should have called it World Trade Center lung disease, because it has a greater definition to it.

GUPTA (voice-over): And because coughs -- well, they typically go away. For many firefighters, the cough persisted. In fact, it got worse. What would take its place was an inability to breathe.

Dr. Prezant watched the tragedy unfold.

PREZANT: Three years before 9/11, their lung function was declining 30 millimeter per year, which is infinitesimally small amount, typical of what average middle aged man have just to the aging. In the first six months after 9/11, on average, they dropped 370 milliliters, 12 times what they, themselves, were decreasing just due to aging. That is unheard of.

GUPTA (on camera): An Marty?

PREZANT: Marty was over 1,200 milliliters.

GUPTA: So, 40 times?

PREZANT: Forty times, yes.

FULLAM: Come in.

GUPTA (voice-over): Prezant, who's one of Marty Fullam's doctors, knew for sure that the dust was affecting Marty's lungs. But there was something else. His immune system was turning on his body, attacking his muscles and eventually his lungs.

FULLAM: I went in the hospital, I weighed 220 pounds. After three weeks, I weighed 155 pounds.

GUPTA (on camera): Sixty-five-pound weight loss in three weeks?

FULLAM: Yes. I walked into the hospital and three weeks later, I couldn't walk. I couldn't breathe.

CHRISTIE WHITMAN, THEN-EPA COMMISSIONER: Well, if there's any good news out of all of this, it's that everything we tested for, which includes asbestos and lead and VOCs, have been below any level of concern for the general public health. Obviously, for those who are down here, these are very important.

GUPTA (voice-over): In September of 2001, there were reassurances, but the testing required to make any statement about air quality had not been completed. So, could anyone really say the air was truly safe?

(on camera): September 18th, the EPA commissioner kind of waved the all clear sign. Was that appropriate from what we know now?

ANTHONY DEPALMA, THE NEW YORK TIMES: No, it was not. It definitely was not. She did not have enough information to make that statement.

GUPTA (voice-over): Anthony DePalma covered 9/11 for "The New York Times." He's the author of "City of Dust."

(on camera): Most people worried about the potential health impacts of this dust at the time 10 years ago.

DEPALMA: This was something that anyone who watched the videos from that day saw. They saw that thunder cloud of dust coming around the building like some sort of a science fiction monster. They knew that it was not safe, and yet the government was telling and continuing to tell them it was safe. They were desperate for some kind of answer.

GUPTA (voice-over): The former EPA commissioner says that answers were given. That in the weeks following the attacks, EPA officials repeatedly warned of the risks to workers at Ground Zero, and noted the difference between the air quality at the site and the air in the rest of New York City. "We shouldn't seek a scapegoat," she adds, "other than those who are indeed to blame for the lives lost that day -- the terrorist who attacked our nation."

So, what was it that made Marty Fullam sick, along with so many other first responders? I'll take you inside the room where they in store the plumes, a place like you've never seen before.

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GUPTA (voice-over): The day after 9/11, dust and smoke float like mist over Lower Manhattan.

(on camera): Most people will never forget those images of that dust. But if you walk around New York City today, there are very few reminders of it. So, it may surprise you to know that so much of the dust was, in fact, collected, it's been studied, and it's been stored for the last 10 years by Dr. Paul Lioy.

And for the first time ever, he's given us a look inside the cold room.

(voice-over): Lioy is one of the country's leading experts on environmental toxins, a professor at Robert Wood Johnson Medical School.

His cold room is a near freezing controlled environment where he has stored Ground Zero dust for almost a decade.

GUPTA (on camera): Here it is. This is the cold room.

DR. PAUL LIOY: This is the cold room where we store it.

GUPTA: Is this it in this bin here? LIOY: Yes. Each one has a manifest on it saying when it was sampled, who it was collected by, who analyzed it, where it was stored, what the initial weight was

GUPTA: You know, there are not a lot of reminders when you walk around the city of New York, thankfully. These are the few reminders that are left.

LIOY: Sure.

GUPTA: If you asked you to name how many particles and what they were in the dust, could you do it?

LIOY: Not without a sheet because we found so much stuff. You got fire retardants. You got combustion products, you know, plastics and other parts of the periodic table.

GUPTA (voice-over): Gold and mercury from tens of thousands of fluorescent light bulbs. Lead from thousand from thousands of computer monitors. Titanium from paint on the Trade Center walls. Asbestos that coated lower beams of the Trade Center buildings.

There was cement, glass, carpet fibers, ceiling tiles, even human hairs. In all, 1.5 million tons of the stuff.

LIOY: You had burning aircraft. You had burning furniture. You had burning, burning material included the jet fuel. We don't know what the initial gasses were in the initial complex mixture that was inhaled by everyone because no one could measure it. That's the great unknown in this.

GUPTA (on camera): Will it always be unknown?

LIOY: Yes. It will always be --

GUPTA: There will always be mysteries about the dust.

LIOY: Yes.

GUPTA (voice-over): What is not a mystery is that thousands of the first responders breathing it in, the health effects were immediate.

PREZANT: The dust was incredibly irritating. When you look at this dust under the microscope, the edges were incredibly rough. They are not smooth edges, this was burning -- their noses, their tongues, the back of their throat and their airways. Every breath was a burning sensation.

GUPTA (on camera): What did it do to the body? What did it look like?

PREZANT: Immense redness. Normally, the membranes of our airways from our nose, all the way down into our lungs are almost white. They are not bright red. They are not looking like they have been all scratched. That's what these airways look like when you put a scope down and see it.

GUPTA: It was like sand paper, literally in the lung tissue. You expect it to get better once they stop getting exposed. A lot of people never did.

PREZANT: Never did.

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GUPTA (voice-over): Marty Fullam and his brother, David, both New York City firefighters will never forget what it was like at Ground Zero. The destruction. The smell. The dust.

UNIDENTIFIED MALE: It permeated in every part of your body. You could not escape it. It was everywhere.

What do you start doing? What do you do?

FULLAM: We searched other surrounding buildings and the sidewalk to see if anybody was under anything, you know?

GUPTA (on camera): (INAUDIBLE)

FULLAM: For people, anybody who was stuck or still alive.

GUPTA (voice-over): It was all that anyone there could do. Dig. Rescuers like the Fullam brothers were mindful of saving lives. Mindless of the dust -- the danger surrounding them.

FULLAM: I knew it wasn't good for my health, but initially there was a chance you would find somebody. And the risks seem to outweigh the danger, you know?

GUPTA (on camera): When was the first time you were offered a mask?

FULLAM: Probably three for four days after that. They had the paper ones they were giving out. And that's what will use from them.

GUPTA: The problem is there is no seal on these masks. So, dust can enter from here, it can enter from here, even through the paper itself. I better option for Marty and the other responders would have been a respirator like this.

A lot of workers who did have access to these respirators said they were reluctant to use them because they were hot. They were uncomfortable. And responders worried they would hamper communication.

Were you ever offered a proper mask that would have protected you?

FULLAM: Much later on.

GUPTA: How long?

FULLAM: Probably a month and a half later.

GUPTA: You guys were the frontline?

FULLAM: Yes.

GUPTA: It took six weeks to get you a mask?

FULLAM: Yes.

GUPTA: To give yourself the best chance at life?

FULLAM: OK.

GUPTA: That doesn't make sense to me.

FULLAM: I wish I would have had it.

GUPTA (voice-over): But here's where it gets complicated. For several days after 9/11, respirators for firefighters were located at a staging area off site, nine miles from Ground Zero.

Marty's brother David got his respirator on the way to Ground Zero. While Marty who live on the other side of the city went straight to the pile.

For Marty Fullam, nearly every breath is now a struggle.

FULLAM: My body craves the extra oxygen.

GUPTA (on camera): What do you feel?

FULLAM: It's like after about a minute or two, as though somebody is holding your head on the water.

GUPTA (voice-over): That feeling of slow suffocation started four years after Marty's work at Ground Zero.

FULLAM: Spring of 2005, I failed a stress test. The technician giving me the test told me that my lungs weren't producing enough oxygen and I never had anybody tell me that before. I started to get weaker every day and sleep more and more every night. Muscle pain and difficulty breathing.

GUPTA (on camera): And you never had anything like this.

FULLAM: No, I never had anything --

GUPTA: Where was it coming from?

FULLAM: I didn't know.

GUPTA: But now, we do know -- something was eating away at his muscles and that something was also eating away at his lungs. All of it, his doctors believe, caused by dust.

(on camera): Body's immune system is literally attacking its own normal tissue.

PREZANT: That's why we call this an autoimmune disease.

GUPTA: How would breathing in dust cause an autoimmune problem?

PREZANT: The chemicals that are coating that dust and the chemicals that were in the gases released that day causes inflammation. And some of us, most of us, that inflammation occurs for a while and goes away.

In other people, for reasons we don't know, the inflammation continues.

And this is Martin Fullam's chest x-ray.

GUPTA (voice-over): Dr. David Prezant is one of the doctors caring for Marty.

PREZANT: Normal people breathe about 10 breaths per minute when they're at rest. But in Marty, the lungs are much smaller, so he has to breathe, 20, 30, 40 times a minute, and yet, each time he has to stretch a very stiff fibrotic, scarred lung.

Squeeze my hand tight.

GUPTA: By 2009, Marty had been diagnosed with pulmonary fibrosis and a rare autoimmune disease called polymyositis.

PREZANT: Before 9/11, we were tracking our firefighters and we did not have a single case of polymyositis. Since 9/11, including Marty, we have about five cases of polymyositis. Five cases, you would say, is a small number. But five cases compared to zero, compared to a population of middle-aged men that you would expect none in, five cases is a lot.

GUPTA: Something stirred up a full-on revolt in Marty's body and he was dying. The only option doctors had to offer, a lung transplant.

PREZANT: Marty was on constant oxygen. He couldn't go to the bathroom without it turning up his oxygen because he couldn't -- wouldn't be able to make it from his bed to his bathroom. That's how short of breath he was.

Marty got a lung transplant and that changed his life.

GUPTA (on camera): Did the lung transplant make you feel better?

FULLAM: Yes, it did. Initially, it did.

GUPTA: What was different?

FULLAM: I could breathe without supplemental oxygen initially. GUPTA: There's a picture of you, I think, surrounded by family and a bunch of firefighters, everyone looks pretty elated. Do you remember that picture is this.

FULLAM: Yes.

GUPTA: How were you feeling?

FULLAM: I felt good I was going home.

GUPTA (voice-over): That feeling of being home, of breathing easy, would be short lived. The worst possible outcome in just a few months time, Marty's body began rejecting his new lung.

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GUPTA (voice-over): Marty Fullam is getting ready for his second lung transplant.

(on camera): How are you feeling today?

FULLAM: I'm doing well today.

GUPTA (voice-over): Since his lungs were damaged at Ground Zero 10 years ago, that includes therapy, a regiment of pills --

FULLAM: It's about 40 pills a day.

GUPTA: And undergoing painful treatments.

But despite all that effort, Marty's lungs are slowly failing him.

(on camera): How sick is Marty?

PREZANT: Marty is as sick as can be. Marty is still alive because of his ability to persevere.

GUPTA (voice-over): But that may not be enough to help him breathe again. And just recently he found out whether he will get the transplant that could save his life.

FULLAM: I was being considered to be listed again for a second transplant, and then a month ago, they told me no, I wouldn't be considered.

PREZANT: With Columbia not wanting to do the second lung transplant because of your inflammatory lung disease from the --

GUPTA: A new lung was his only option. His only hope.

PREZANT: Breathe in and out. GUPTA: Without a transplant, Marty has one, maybe two years.

FULLAM: At some point, I will get sick from the hospital being on a respirator probably and that will be it, which isn't what I wanted to hear. But --

Emma, I love you.

KID: I love you too, daddy.

FULLAM: Give me a kiss.

GUPTA (on camera): You got three daughters?

FULLAM: Yes. And I realize I'm not going to get old with them. Very unlikely that I'll live to older age, but right now, I have my time with them, you know, which is good.

GUPTA (voice-over): And Marty Fullam says he won't stop fighting, petitioning other hospitals to get that transplant.

FULLAM: Five and a half years ago they told me I had two years to live and here it is five and a half years later, I'm still alive. So, I must be doing something right.

GUPTA: It is the enduring symbol of 9/11 -- dust.

DEPALMA: That is kind of a metaphor for the problems that came up afterwards because we couldn't see or were unwilling to clear away the dust to look at exactly what was happening.

GUPTA: A symbol of missteps.

RUDY GIULIANI, FORMER NYC MAYOR: There are no dangerous substances in the air.

PREZANT: The hardest thing for someone in power to say is "I don't know." There's nothing wrong in saying "I don't know" early on in a disaster because the truth is, we don't know.

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GUPTA: As you can see, much more of my investigation on the long-term health fallout from Ground Zero. It's called "Terror in the Dust." That's tonight 9:00 Eastern, right here on CNN. That does it for SGMD.

Time to get you a check of your top stories this morning with Mr. T.J. Holmes and "CNN SATURDAY."